Add focused Jest edge-case tests, update lockfile and changelog

[cruddasj]

Motivation

• Increase Jest coverage quickly by adding small, targeted tests that cover fallback and edge-case behavior not exercised by the existing smoke suite.
• Ensure repository dependencies are refreshed to latest compatible patch/minor releases before adding tests per repository guidance.
• Keep the changelog and in-app changelog data in sync using the required [NEXT_VERSION] / [NEXT_DATE] placeholders.

Description

• Added a new non-overlapping test suite tests/app.coverage-extra.test.js that exercises theme fallback, collapsible-state pruning, go-settings navigation, confirmation modal fallbacks, and empty changelog/version fallback paths.
• Ran npm update and refreshed the package-lock.json to pick up compatible patch/minor updates to dev dependencies.
• Inserted a [NEXT_VERSION] / [NEXT_DATE] entry into CHANGELOG.md and prepended a matching placeholder entry to assets/changelog.json per the repository policy.

Testing

• Ran npm test -- --runInBand which completed with all tests passing (14 passed) and increased assets/js/app.js coverage to ~87.9% statements.
• Ran npm run lint which passed (no lint errors reported).
• Verified the new test file tests/app.coverage-extra.test.js does not duplicate scenarios already covered by the existing smoke tests and focuses on edge/fallback behavior.

---

Codex Task

[github-actions]

Coverage report

St.❔	Category	Percentage	Covered / Total
🟢	Statements	87.94% (+6.33% 🔼)	722/821
🟡	Branches	69.15% (+8.61% 🔼)	139/201
🟢	Functions	89.74% (+2.56% 🔼)	35/39
🟢	Lines	87.94% (+6.33% 🔼)	722/821

Test suite run success

14 tests passing in 2 suites.

Report generated by 🧪jest coverage report action from 48f380e